Sharpening machine for curved blades



y 3- w. E. NICKERSON SHARPENING MACHINE FOR CURvED BLADES 7 Sheets-Sheet 1 Filed Jan. 20, 1928 gave? y w. E. NICKERSON 0 ,88

SHARPENING MACHINE FOR CURVED BLADES Filed Jan. 20, 1928 '1 Sheets-Sheet 2 fgzveni or y 1933- w. E. NICKERSON SHARPENING-MACHINE FOR CURVED BLADES Filed Jan. 20, 1928 7 Sheets-Sheet 3 May l6, 1933. w. E. NI'CKERSON I SHARPENING MACHINE FOR CURVED BLADES 7 Shets-Sheet 4 Filed Jan. 20, 1928 y 1933- w. E. NICKERSON SHARPENING MACHINE FOR CURVED BLADES 7 Sheets-Sheet 5 Filed Jan. 20, 1928 y I w. E. NICKERSON. 1,909,334

SHARPENING MACHINE FOR CURVED BLADES Filed Jan. 20, 1928 7 Sheets-Sheet- 6 y 1933- w. E. NICKERSON SHARPENING MACHINE FOR CURVED BLADES Filed Jan. 20, 1928 7 Sheets-Sheet 7 Patented May 16, 1933 UNITED STATES PATENT o FicE WILLIAM E. NICKERSON, or BOSTON, MASSACHUSETTS, AssIGNon o GILLETTE AFETY RAZOR COMPANY, or BOSTON, ranssnonnsnr'rs, A conronnrron on DELAWARE SHARPENING MACHINE FOR CURVED BLADES Application filed January 20, 1328. Serial No. 248,224.

This invention'relates to machines for sharpening cutting blades and its principalv object is to provide a machine capable of sharpening blades having compound edge curvature, that is to say blades having different portions of their edges curved on different centers of curvature.

In one of its aspects the invention consists in an automatic machine having a sharpening element, such as a grinding or honing disc, and a blade holder movable relatively to each other for bringing all'points of the edge of a compound curved blade automatically and progressively into sharpening position.

The invention is herein shown as embodied in a machine for grinding or honing theedge of a detachable or replaceable blade, such as is used in surgical knives or the like. The

edge of this particular blade is formed in two curves, a curve of short radius near the point merging into a curve of long radius in the body of the blade. This isone example of the type of blade with which my invention is concerned.

The invention contemplates also the provision of means in an automatic sharpening machine for accurately determining-and adjustably controlling the length, location and point or points of tangency of the different portions of the compound curve of a blade edge. V

These and other features of the invention will be best understood and appreciated from the following description of a preferred embodiment thereof, selected for purposes of illustration and shown in the accompanying drawings, in which Fig. 1 is a plan view of the machine.

Fig. 2 is a view in elevation of the actuating mechanism for the blade holder.

Fig. 3 is a view in elevation illustrating particularly the blade holder and its clamping mechanism.

Fig. 4 is a sectional view of the mechanism shown in Fig. 8.

Fig. 5 is a plan view, on an enlarged scale, of the machine with the blade holder in grinding position.

Fig. 6 is a detail view in section of a portion of the locking mechanism for the blade holder. v 1

Fig. 7 is a plan view showing the blade holder in position for sharpening the blade on the long radius of curvature. Y x 5 Fig. 8 is a plan view of the blade holder with the lower plate removed.

Fig. 9 is a plan view of the lower plate of the blade holder, showing the location of the blade in dotted lines. 7 v Fig. 10 isaplan Viewsimilar to Fig. 7 but showing the blade holder in position for sharpening the blade on the shortradius of curvature. v p H Fig. 11 is a plan View. similar to Fig. 7 but showing the blade holder inloading position, and y l v Fig. 12 is a plan -view, more orless in diagram, showing 'the locating stops for the blade holder. V v The machine herein shown comprises, as its principal units, a blade clamp or holder movable successively about two centers, (2) blade clamping mechanism, actuating mechanism for moving the holder, (4) coning the path and position of the holder at various points in its cycle, and (5) grinding er sharpening mechanism. These units will bev described in the order in which they are above enumerated.

The blade to be sharpened is designated in the drawings by the reference character B and is well shown in Fig. 9. It has a straight back edge and a' cutting edge. formed on two tangent arcs, that atthe tip of the blade having a center of curvature at B ona short radius and that in the body of the blade having a center of curvature at B on a relatively long radius. The shank of the blade terminates in a circular projection which isuseful in retaining the blade when assembled in its handle. I I

A rectangular base plate 10 carries the different units of the machine and affords a rigid support therefor. A standardv 40 is bolted to the base plate 10 and provided with a pair of forwardly extending lugs 41 and 42 for a vertical pin or shaft 44. Keyed to the shaft 44 is a bracket 46 which carries the trolling mechanism for accurately determinblade holder, see Figs. 3 and 4. The upper end of the pin 44 is protected and an oil chamber provided by sinking a ring 45 into the upper surface of the lug 41 concentrically with respect to the pin 44 and projecting above the surface thereof sufficiently to retain a dust cap 47.

At its outer end, bracket 46 is provided with a boss 48 in which is set a vertical pin 50 having a shoulder "arranged to turn upon the upper surface of the boss. The blade holder 52 is secured to the pin 50 and turns with it. At its upper end, the blade holder is provided with a pair of blade clamping members, comprising a bottom plate 54 rigidly secured in place by screws and a hinged cover plate 56 arranged to swing on a horizontal axis and having a hardened curved wear piece 57 set in its upper surface. The stationary clamping plate 54 is provided with three blade locating pins 55, as shown in Fig. 9. Two of these are adapted to bear against the rear straight edge of the blade to be sharpened and the third projects through an aperture in the blade itself. The lower clamping plate54 extends laterally sufliciently to support practically the entire blade. The upper clamping plate 56 is narrower and engages the blade only opposite the portion of its edge to be sharpened. The upper clamping plate 56 is normally swung upwardly into open position by a torsion spring 58 surrounding its hinge pin, and is swung in the opposite direction or into blade clamping position by fluid pressure operated mechanism.

The bracket 46 is provided with an upwardly extending arm 60 having a head 62 to which is secured a stationary piston 64, which cooperates with a movable cylinder 66. Compressed air is conducted to the head 62 by a tube'68 and admitted through a port 7 0 in the piston to the upper end of the cylinder. The upper end of the cylinder 66 is l closed by a plate 72, having upstanding ears between which is mounted a rocker member 74. The forward end of the rocker member is connected througha vertical link 76 to an ear on the stationary head 62. The rear end of the rocker member is connected through a vertical link 78 to a clamping lever 80 pivotally mounted in the upright arm 60 and adapted to engage the wear piece 57 of the upper hinged clamping plate 56. It will readily be seen that when compressed air is ad- It will be noted, moreall positions of the latter. The admission of compressed air to the cylinder 66 through the tube 68 is controlled and properly timed with reference to the cycle of the machine by overhead controlling mechanism of the character disclosed in my prior Patent No.

- 1,285,590, granted August 7, 1917, to'which reference may be had.

. As will be seen from the foregoing description, the blade holder 52 is capable of swinging about the axis of the vertical pin 44, which moves the blade to be ground on a long radius, and also about the vertical axis of the vertical pin 50, which moves the blade on a comparatively short radius. In its movement about the vertical pin 50, the blade holder is constantly urged in a counter clockwise direction by a chain 82, secured by a pin between a pair of flanges forming a drum in the body of the holder and being wrapped end is anchored in the boss 89 so that it tends at'all times to rotate the shaft 88 in a clockwise direction. The collar 92 is adjustably secured to the shaft 88 by a set screw, not shown and may be set in different positions to regulate the tension of the spring 94 and so secure the proper speed of movement in the blade holder 52. It will be noted that the drum 86 is carried bodily with the bracket 46 so that its action is uniform in all positions of the blade holder.

A second standard 12 is secured to the base plate 10 and provided with bearings for a horizontal shaft 14 carrying at its outer end fast and loose pulleys161 and 162. The

standard 12 has also bearings for a vertical shaft 16, carrying at its lower end a large bevel gear 18 which is drivenby a smaller bevel gear 20, keyed to the shaft 14. At its upper end the vertical shaft 16 carries a crank disc 22, in which a crank pin 24 is mounted for radial adjustment.

Movement of the blade holder in opposition to the yielding movement produced by the chain 82 and spring 94 is derived from the crank disc 22 through the medium of a long horizontally disposed link 100. This link is pivotaliy connected at its forward end to a pair of radially disposed ears 102 projecting from the blade holder 52. The rear end of the link is formed as a slide-way for a block 104, into which the crank pin 24 projects. A longitudinally disposed adjusting screw 106 determines the point of engagement of the crank block 104 with the link parts disposed as shown in Fig. 11, move-' ment of the link 100 toward the left will swing the blade carrier 52 so as to carry the ear 53 away from the stop screw 61 and unwind the chain 82 in opposition to the spring 94. This movement of the blade holder continues until the car 53 encounters the stop screw 59 as shown in Fig. 10. When this occurs, it will be apparent that further movement of the link 100 will tend to swing the whole bracket bodily about the axis of the vertical pin 44. While the link 100 has been referred to as producing movement of the blade holder 52 about the axis of the pin 50, it also produces this movement about the axis of the pin 44, as will now be explained.

The bracket 46 is provided with a laterally extending arm 110 oppositely disposed to the arm 90 and pivotally connected at its lower end to a link 112 which, in turn, is connected to the lower end of the vertical arm of a bell crank lever 114 mounted to swing upon a horizontal shaft 116 projecting from the standard 40. A torsion spring 118 surrounds a portion of the shaft 116 and tends at all times to swing the bell crank lever forwardly at its lower end, so as to oscillate the bracket 46 in a counter clockwise direction. This movement is opposed and controlled by a. vertical link 115 connected to the transverse arm of the bell crank lever at its lower end and extending to overhead cam controlling mechanism of the character shown in my prior Patent, No. 1,235,590, above identified. The movement transmitted to the bracket 46 through the bell crank lever 114 is for the purpose of swinging the blade holder about its long radius for moving the bracket from loading position, as shown in Fig. 11, to grinding position shown in Fig. 7, and back again. \Vhen the bracket and blade holder are in loading position, as shown in Fig. 11, the link 100 is moved rearwardly so that the oscillation of the crank block 104 takes place in the guideway of the link and-entirely out of contact with the adjusting screw 106. On the other hand, when the bracket is moved into grinding position, as in Fig. 10, the link 100 is drawn forwardly to such a position that the crank block 104 will in its oscillation encounter the adjusting screw 106 and link 100, on the one hand, and the springs 94 and 118 with their connections, on the other hand. If the sharpening operation is considered as beginning at the point of the blade as suggested in Fig. 10, the link 100 will begin to move toward the right and permitthe spring 94, through the chain 82, to swing the blade holder on its short radius. The spring 94 isstronger than the spring 118 so that the entire movement of the link 100, up to the point when the ear 53 encounters the stop screw 61, is taken up in the oscillation of the blade holder about the axis of the pin 50. This movement carries the blade on a short radius of curvature to the point of tangency of the two curves in its edge. From this point on continued movement of the link toward the right permits the spring 118 to swing the blade holder on its long radius about the axis of the pi1r4'4, thereby sharpening the portion of the blade which is curved on the longer radius.

Locking means will now be described for holding the bracket 46 against movement during the swinging of the blade holder on the axis of the pin 50 and for unlocking the bracket and limiting its oscillation about the axis of the pin 44. Alstandard 130 projects from the base plate 10 and is provided with ahorizontally disposed adjusting screw 132, adapted to bear against the side of the bracket 46' and limit its movement in a counter clockwise direction. Fig. 7 shows the bracket 46 as moved to the limit 'of its oscillation in this direction and in contact with the adjusting screw 132. Still another standard 140 is secured to the base plate 10 ina position to the left of the bracket 46. The standlocking member is the longer and carries an adjustable stop screw 154 adapted, when in the position shown in Fig. 7, to limit the movement of the bracket 46 in a clockwise direction inits oscillation through the angle D, Fig. 7, in grinding the long radius curvature of the blade. The shorter arm 146 of the locking member is provided with an adjustable stop screw 156, which may be positioned alternately to the stop screw 154,

permitting an oscillation through a greater angle C, Fig. 11, of amplitude to the bracket 46 but, as before, determining the final position of the bracket in a clockwise direction.

The locking member 144: is pivotally connected through itsarm 1 18 by a link 160 to the vertical arm of a bell crank lever 162 pivotally mounted upon a pin 163- projecting from the side of the standard 40. A spring 164 tends to swing the bell crank lever 162 so as to carry the link 150 forwardly and this motion is opposed and controlled through a vertical link 166 connected to and actuated by the overhead mechanism of my patent above referred to.

The grinding means iitself forms no part of the present invention although is constitutes an element of many novel combinations defined in the claims. As shown in Fig. 1, it comprises a thin abrading disk32 carried on the outer end of a shaft 34: mounted in a bracket 30 and driven at high speed from any convenient source of powerynot shown. A similar abrading element is illustrated in complete detail in my copending application Serial No. 215,238, filed August 2 1, 1 927, to which reference may be had. It will be understood that the bracket 30 maintains the abrading disk established in the position shown in Fig. 1 during the operation of the machine and that the relative movement of the blade holder and the abrading disk contemplated by the present invention takes place, in the illustrated machine, as movement of the blade holder while the abrading disk occupies a defined position. This position is such that the abrading point on the periphery of the disk 32 lies in line with the two centers of movement of the blade holder, and corresponds to the point oftangency f the two constituent curves of the blade when the blade has been moved to the position wherein the sharpening operation passes from one curve to the other.

The operation of the machine will be apparent from the foregoing description but may be concisely outlined as follows. The blade holder is first-swung clockwise on the axis of the shaft 1% through the angle C to its loading position, as shown in Fig. 11, by the action of the overhead mechanism through the arm 110, and th blade clamp plate 56 is swung into its open position so that a blade to be sharpened may be placed in the blade carrier against the locating pins 55. The blade may be supplied by hand or by automatic feeding mechanism, such for example as that shown in my prior Patent No. 1,255,917. hen the blade has been so located, compressed air is admitted through the control mechanism in the cylinder 66 which thereupon acts to close the clamping plate 56 through the lever 80 and maintain the blade firmly in position and under suriicient pressure to insure against its displacement.

The overhead mechanism then acts again through the arm- 110 to swing the blade carrier toward the right, as seen in Fig. 11, through the angle 0' to its initial grinding position (indicated in Fig. 10) wherein the abrading disk 32 is shown as engaging the extreme point of the blade and the ear 53 engaging the stop 59. The crank disk 22 new arrives at a position whereinrthe link 100 is permitted to move toward the right and the blade carrier 52 is swung through the angle E about its own axis 50, carrying that portion of the blade beneath the abrading disk which has the short radius of ourvature. This initial grinding movement is terminated when the car 53 of the blade holder encounters the adjustable stop 61. Ther-eupon, and without interruption, move ment of the, blade holder continues toward the right. through the angle D (Fig. 7) about the axis of the shaft A l and that portion of the blade which, has the long radius of ourvature is carried beneath the abrading disk. The long radius movement continues until arrestedby the adjustable stop 132, which thus determines the point on the blade at which the grinding operation ceases. At the same time, the crank f isk 22 has reached such a position that th link 100 begins to move toward the left and return movement of the lade carrierin its curved path ensues continuously in reverse sequence. The vibration or oscillation of the blade carrier is repeated often as necessary to complete the grinding of one side of the blade. In practice, three or four complete vibrations are often employed. At the conclusionof the operation, the overhead mechanism again acts through the arm 110 to swing the carrier to leading position and the cycle of the machine is completed when the machine comes to rest in this condition. During the movement of the machine as above outlined, the locking member la lis operated in the proper time relation to determine the two positions of the blade carrier which is its function to determine and compressed air is admitted to and exhausted from the cylinder 66 at the proper time to clamp and unclamp the blade in its holder.

()ne side of the blade having been sharpened, the blade is removed from the machine and presented other side uppermost to a similar but reversely assembled machine in which the blade is fed beneath he abrading disk in the reverse direction, and a corresponding sharpening operation performed upon the other side of the knife edge.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is: I

1. A machine for sharpening blades, com prising an abrading device, a swinging blade carrier having blade clamping means, and actuating mechanism for the clamping means including a fluid pressure cylinder and operating connections mounted upon and movable with said carrier.

2. A machine for sharpening blades, comprising an abrading device, a. blade carrier comprising a member having blade clamping means and being pivotally mounted in a second swinging member, a fluid pressure cylinder mounted on said swinging member, and a lever operated thereby and so located as to engage the blade clamping means at a point in line with the axis of the pivotally mounted member.

3. A machine for automatically sharpening blades of compound edge curvature, comprising a sharpening element, a blade holder including means for locating and holding a blade in position to have one side of said edge engaged by said element, mechanically actuated means for causing such relative curvilinear movements between the sharpening element and holder as to progressively engage the blade and uniformly bevel all of said side along said compound curvature, and means for adjust-ably controlling the length and location of each portion of the curve.

4. A machine for sharpening blades of compound edge curvature, comprising a sharpening element, a blade holder mounted for movement about different centers while keeping the edge of a blade'thercin in sharp ening contact with said element, springs acting to move the holder in one direction about each center, and positively acting mechanism for moving the holder in the other direction in a continuous manner about one center after another.

5. A machine for sharpening blades, comprising a sharpening element, a pivotally mounted bracket, an oscillatory blade holder mounted therein in operative relation to the sharpening element, a spring actuated drum carried bodily by the bracket, and a flexible operating connection between the blade holder and drum for oscillating the blade holder in one direction relative to the sharpening elements.

6. A machine for sharpening blades, comprising a sharpening element, a movably mounted bracket, an oscillatory blade holder mounted to receive a movement bodily in a defined curved path upon movement of the bracket, the blade holder having a blade clamping jaw in operative relation to the sharpening element, spring operated mechanism carried by the bracket for maintaining the blade holder normally at one limit of its oscillation, and an adjustable stop for determining such limit.

7. A machine for sharpening blades, comprising a sharpening element, a movable carrier member, an oscillatory blade holder mounted therein in operative relation to the sharpening element, a constantly moving actuator for the blade holder, and means for so moving the carrier member as to interrupt the action of said actuator upon the blade holder.

8. A machine for sharpening blades, comprisinga sharpening element, a movable carrier member, an oscillatory blade holder mounted therein in operative relation to the sharpening element, and power operated mechanism for mechanically imparting to said holder'a movement bodily in a-defined curved path and beingarranged to act automatically upon movement of the carrier member to a predetermined position and cooperating adjustable means for defining the limits of said bodilymovement.

9. A machine for sharpening blades, comprising a sharpening element, an oscillatory carrier, a blade holder thereon operative relation to the sharpening ,element, yielding relation to the sharpening element, an adjustable stop for determining the limit of carrier movement in one direction of its oscillation, and a shiftable stop having arms of unequal length for determining alternative positions of limit of carrier movement in the other direction of its oscillation.

11. A machine for sharpening blades, comprising a rotary sharpening element located in an established position, a blade holder in operative relation to the sharpening element, power operated means for moving the blade holder relative to the sharpening element first about an internal axis and then about an external axis, back and forth in continuous oscillation, and for moving the blade holder temporarily for-loading purposes to a position outside its path of oscillation.

12. An automatic machine for sharpening blades of compound edge curvature, includ ing a blade holder movable successively about spaced axes, a co -operating abrading device, power means operating to move the vholder, first about the more remote of the two axes and then about the nearer axis, the entire movement of the holder being a continuous oscillation, whereby a smooth sharpened edge of compound curvature is produced, and stops which co-operate to define the limits of the movement of the'blade on each curve. 13. An automatic machine for sharpening blades of compound edge curvature, including a frame, a bracket pivotally mounted thereon for movement about a fixed axis constituting one center of edge curvature of the blade, a blade holder carried bodily by said bracket and being pivotally mounted therein for movement about another axis located at a fixed distance from that first mentioned and constituting another center of edge curvature, power operated means for successively eflecting the tWo movements, and stops which cooperate to define the limits of said movements. 7

14. A machine for sharpening blades of compound edge curvature, comprising a blade holder, power actuated mean-s for oscillating f the blade holder successively about spaced axes so located as to correspond With centers of blade curvature of different radii but tangent relation, and a rotary abrading Wheel driven about an axis inclined to the normal of the blade edge curvature at the point of contact. 7

Signed at Boston, Massachusetts, this 17th day of January, 1928.

WILLIAM E. NICKERSON 

